Camshaft position sensor location

You've had a productive time! Nice work cleaning up the oil sump and pickup screen, it's still on my to-do list.

When reinstalling the camshafts, pay particular attention to the bearing saddle bolt torque sequence and thrust bearing seating process. It's all in the shop manual. I was able to pull mine without removing the exhaust camshaft just following the shop manual, but breaking the big actuator bolt loose was a bear.

Which spring are you referring to as being jammed? The one on the lock pin?

 

Yeah, the the plunger type thing inside the actuator. And once apart and cleaned, I could use air by blowing on one of the holes where the cam inserts into that thing, and I can hear it operating now.

Hey how did you get the bolt out on the intake cam, I mean once you got it lose. It'll only come out 1/2 way before it hits the timing cover. I undid the exhaust cam because I didn't want to fight that little chain too. Oh well, I'll read the manual next time.
And yeah, that bolt was in there lol... here ya go lol

 

Thanks for the tips on the bearings... I better read that.

 

Yeah do it. If the engines are the same, its real easy. I used that red high temp stuff when I put it back. Let it sit up for about a 1/2 hour before you put the pan back on.
If yours had more sludge than mine... do it!!!!!! Tbh, when I saw that screen.... I have no idea how the engine was getting any oil at all. I wish I'd taken a picture, it was horrible.

Do it brutha! Clean that b*tch!

 

Is that a used engine, or the original? Due to all of the sludge.

During my recent adventures with the intake cam gears, I had some spare to reassemble and swap for my static set. The problem that I encountered was that I could not find any torque specifications for the tamper proof bolts.

Maybe your manual has that specification? If so please share that!

I apparently over torqued them. They would not phase as intended, so I ended up buying two new ones from Rock Auto. The Standard Motor Products ones, listed a few pages back.

 

Hi Tors,
Its the original engine, I bought the truck new. So yeah unfortunately all that sludge is my bad, sort of, but the buck stops with me. I let the gf use it for a long time, and I just forgot to change the oil. It was pretty low. Of course she never said anything about anything... but whatever on that.

Regarding the torque on those things. Interesting that you brought that up, I was logging on to post an update. I just put them back on there tight, sequentially of course on tightening them. I figured there was no way I'd get them as tight as they were originally and they were certainly tight enough when I was done. Confident with my "highly calibrated feel" (as one of my old Senior-Chief's used to jokingly say when he'd check work done by his subordinates) I had them all equal.

But after that, I had a hell of a time with the thing. For some reason the cam didn't want to go in as easily as it came out. Then when I bolted it on, that outer plate, ( the one with the funny shape that is used as the pickup for the cam position sensor) , even though it would rotate back and forward freely (I'm taking care to avoid the locked position), as soon as I put any tension on that cam bolt, the damn thing would lock up. It wouldn't budge. It makes absolutely no sense.

After an hour of various things including sanding etc, I took it all apart and filled it with oil. Everything appeared to work, but then in messing with it, I bumped into the locked position. Now that's no big deal because you can install them like that, as soon as they get get oil pressure, they unlock. But I wanted to test it, so I tried blowing air into the hole on the top of the cam that the oil uses to get in there. I could hear the plunger clicking, but I still couldn't rotate that plate. I figured I just wasn't getting enough air pressure from my hose nozzle as that hole is recessed in the ring on the cam, and since I don't have 3 hands, I said heck with it, it has to work, and went ahead and put everything back together.

Time for the road test. Now I could have just sent the ocv 12V to see what would happen, see if the engine ran rough at idle, but I wanted the thrill of NOT seeing the CEL come on. Drove it a bit, turned it off to enter the 2nd drive cycle, started it back up.... "here we go... creeping up to 40 mph.... here it comes.... 40 mph, no light, you got it(!!!!)... AAAAAh. WRONG!!!!. Bam.... effing CEL. Another neighborhood peace shattering "F****" was certainly heard by anyone working in their yards.

So I don't know. I'll order a new one and mess with it next week. The battle rages on.

 

In the meantime, feeding 12VDC to the oil control valve w/ engine running at idle to check for rough idle result would be a great test. You still haven't completely ruled out timing chain stretch as the cause of the CEL. I'd verify VVT function while it's back together. Also be sure you have the positive-negative polarity correct when you do the test.

 

I don't have a good pic, but the crank was right on the zero and everything lined up regarding the actuator and the line on the bearing saddle, so I feel pretty confident the chain is ok.

There's one test I have not done yet, and that's to check the resistance of the coil on the ocv. But sitting here thinking about it, even if the the ECM sends out a lower voltage than 12V, hitting the valve with a full 12V will certainly do the trick and allow oil to flow and advance the timing.

I just watched a few vids on how these things work, and as I understand it, the ocv actually allows oil to flow in both directions. So when its energized, the oil flows into the port that unlocks the plunger and then fills those chambers thereby advancing the valve timing. When the valve is not energized it allows the oil in those chambers to exit and the timing retards. Apparently the valve cycles on and off quite a bit as speed increases/decreases when operating at higher RPM's. I guess when you are at idle, the valve is not energized therefore the plunger inside the actuator is extended, locking the entire gear. Sending 12V and holding it there will allow the chambers to completely fill and basically advance the timing as far as the system allows.

 

The other thing I have not tested is the cam position sensor, but I don't think I need to because again, by applying 12V at idle, you advance the timing to its stops and you are basically taking the ECM out of the question anyway.

It's gotta be the actuator.

Craig in that picture you posted with your actuator taken apart, did you put it back together and reuse it? I don't recall reading in this thread if you said whether or not you purchased a new one.

The reason I ask, is why are all these things, even different versions on different cars, all assembled with various styles of tamper-proof bolts? And no one wants a core deposit so its not like they did that to make them harder for folks like us to rebuild which would be one's first inclination. I wonder why they do that?

 

Nope, didn't reassemble and reinstall...got a new one as was the case with @Torspd. No clue why Toyota used those crazy bolts.

The thing I'm unclear on is the P0012 logic in Tacoma ECMs as relates to timing chain elongation. On 4Runners and FJ Cruisers, an elongated chain with otherwise-working VVT system causes a P0016. They're built in Japan and may have different software w/ different test logic, no way I can see to check your P0012 other than the shop manual diagnostic procedure.

But w/ no engine behavior change when the oil control valve is manually powered, I agree the VVT actuator is suspect. Also, when you have the intake cam removed again to replace the VVT actuator, blow thru the big VVT oil passage in the camshaft to ensure no obstructions. It's part of the #1 bearing saddle, separate oil circuit that supplies oil from the oil control valve to the VVT actuator.

 

Ya know I thought about it, I bet the reason those tamper-proof bolts are used, and not just by Toyota's OEM supplier, but the other car companies too, I bet the reason is so people won't in fact take them apart and re-assemble them on the chance that one of the bolts may later back out, fall down, and trash the whole darn engine.

Good call on blowing the air through there, and I did in fact do that the first time as I wanted to make damn sure sludge wasn't the problem anymore.

For any future readers of this thread, I put together a decent explanation of how the system actually works but I have to use two videos so you can see what goes on with both components--- the valve and the actuator/modulator.

The first is from a Honda Vtec, but I have the video queued to the part that shows a nice depiction of oil flow through the valve when the valve is energized and then when it is not energized.

The second video shows whats going on with the oil inside the modulator and how it actually advances/retards the timing using the oil coming from or returning to the ocv.
While this is not the exact one on a Tacoma, this particular design is real close to what you'd see inside one off a 4.0L. The only difference is the arrangement of the oil passages really, but you'll get the idea of whats going on. The guy's a Brit lol, he does a good job. Not sure whats up with that ring he wears though.

valve operation:

https://youtu.be/OtRlQrAc5IY?t=110

Actuator operation:

https://www.youtube.com/watch?v=qZbaDZPrl_0

 

Hello Craig!

Break out the band and hand out the party favors. The war is over... the CEL from hell is dead.

So to update, and for posterity-sake should some TW surfer in the future be so dumb as to let their truck run low on oil with a CEL, or maybe buy one that's throwing the P0012 (or the one for the driver side)... that nothing in the world seems to fix... here's how it ended.

Since we last chatted --- I ordered a new VVT Camshaft gear, installed it, put it all back together, drove it ... unbelievable. CEL came back on. Now I'm really frustrated. I checked everything. I hooked up a digital meter in line with the oil control valve and verified the signal from the ECM was there. I even hooked it up to the bank 2 side to make sure they were identical. They were. I measured the resistance of the OCV. It checked. And besides, I KNEW all this was for not because throwing 12v to the OCV should bog down the engine. It takes all the ECM and wiring out of the picture basically. It works like a champ on bank 2. I put 12v over there.... friggin engine bogged down as advertised.

So there I was. New everything.... and nothing worked. On the off chance I thought maybe the OCV from Autozone might have been manufactured incorrectly, IE maybe those ports didn't line up... I took the damn thing back and got another one. No luck.

I went to Toyota where I bought it... now mind you, I have bought 4 new vehicles from this dealership in the last 20 years... so I'm getting my way right? I went into service and asked to talk to a master-technician. Unbelievable... they were soooo nice. The guy at the desk walked me right back to their most experienced mechanic and I told him the whole story. We laughed, I honestly think I impressed him because I had an answer for every one of his questions. Right down to the impedance of the plug to ECM wire harness. He was stumped too. Told me good luck and come back and tell him what it was if I get it fixed.

OK so Sunday night I'm about ready to leave it running down in the hood, walk away, and catch an Uber home.

I keep thinking... its gotta be a f'ing oil problem, that's the only thing it can friggin be... but I blew air thru everything and like I said, I cleaned my pick-up screen, checked the oil pressure, blew air through everything, did 2 flushes with kerosene, the timing chains are on the gnat's ass.... its like wtf!?

So I'm gonna try one more time. Yesterday I took the OCV out, stuffed a rag over the hole and cranked it. Plenty of oil. So the filter is fine. As is the channel from the filter to the valve. Obviously the valve is fine. Next thing is the passage from the valve to the camshaft #1 bearing. I took the valve cover off again for the 20th time.... I removed the top saddle bolt and blew air in those two little ports down to the valve. They were clean. AND THEN EUREKA.... THE LIGHT CAME ON....

See the valve ALWAYS has oil flowing through it. Whether its energized or not. This is key. Not only does it allow oil up to the camshaft actuator, but depending on whether its energized or its off, it allows oil to flow back through it and down to the pan. Thats how it varies the position of the cam. Those two videos above helped me figure that part out. So I realize there has to be a port in the housing that the OCV slips into that basically goes down to the pan with return oil. Problem is, there's no way to get to it to blow air through it. Any place you blow, the air has alternate passages it can go so if that's stopped up... the air won't do the trick. Its impossible to clean, or so I thought. That's when I got creative.

I took the "D" string off of one of my guitars... for those unfamiliar its the 3rd string from the top, and its a pretty strong string... and they are "wrapped" with brass or something like that.


That one is a low E, but you get the idea, the D is just a little thinner.


I cut the the string, and then using needle nose pliers I fashioned a tiny curly-cue on one end by twisting it around a nail. Then with the help of a mirror I worked it into the hole the OCV slides into and I got it started in the port that heads down to the pan. I then attached my drill motor to the other end.

You got it... Ro-Ro-Rotor for a Tacoma engine. I ran the drill and sure enough, i worked it all the way in and down. Pulled it out.... COVERED with tar. Did it a couple more times for good measure... put everything back together.... and headed down the road.

I knew backing out of the garage the truck was fixed. I could just feel it. It ran different.

I blew down the road. Unbelievable difference in performance. No spark-knock at all when I stepped on it. And as I said way earlier at the beginning of my postings on this thread, the truck ran smooth through all of this. But now it ran better.

I shut it down, let it sit, (again, the CEL for bank 1 requires 2 drive cycles to trigger) then fired her up and headed down the road. Boom!. No CEL!

The war has ended.

Soooooo.... aside from ALWAYS RUN CLEAN OIL.... here's what happened.

From the get-go here as I've written above... the original OCV was in fact bad, and it always bothered me that "what are the odds" 2 things in the same system could go out at once.

Here's what I think happened.... when she was driving with CEL on... the valve was bad. It stuck in a position that would not let that oil in that channel drop into the pan. Like your finger on top of a straw. The more she drove it, that oil sat in there and baked. It became solid. All the way down. When I pulled out that guitar string, it wasn't just goo, there were what can best be described as similiar to black pieces of plastic. It was baked oil. And it had completely clogged that channel all the way down. So installing the new valve, made no difference. Oil could make it up to the Cam actuator gear and unlock the pin, but there was no place for it to port back to, hence the gear could never advance the timing. All the flushing and everything else wasn't enough to clear that blockage.

And that's how the story ends.

I remember there used to be a website called 100 things you can do with a used guitar string....

Well, its a hundred and one now.

 

Bravo sir, bravo! Very creative indeed!

 

Wow, this has been a careful, methodical approach to troubleshooting and with a terrific outcome. Very well done and no doubt your post will help somebody else in the future.

 

Where is the camshaft position sensor located at

 

Is the campshaft position sensor the same as the campshaft oil timing Valve

 

No. Oil timing valve controls oil flow to VVT phasers.

 

I found out where the camshaft position sensors are thank you

 

If anybody wants to know hit me up And I will be replacing all the sensors eventually as well

 

I know this is an old post, but in case it helps someone in the future take a narrow strip of gorilla tape over the end of your finger. Sticky side out. Then another strip wrapped around the finger (sticky side in) to hold the first one. Reach down and stick your finger to the filter then carefully remove!

This thread has been great researching my P0011 & P0012 issues. Do you happen to recall the polarity? Wouldn't one way be advancing the cam, and the other polarity would be retarding?